A device of the above-mentioned type is known in the prior art, arranged for use in connection with containers for liquid natural gas (LNG) where there is welded into the pipe an element comprising a first pipe section with the same internal diameter as the pipe, a section which extends radially outwards from this pipe section, and a second pipe section which has a larger diameter than the first pipe section and is connected to the radially extending section and extends coaxially in relation to it. The element's sections are constructed in one piece, e.g. by means of casting.